Available Traction

[stuman]

So I hear/read about how you have to be willing to use all your available traction to go fast. It comes up all the time when talking about braking, how you can only use so much of your max for braking and the rest for turning and stuff.

 

So like, how much traction do you have? How do you know when your using it all?

[faffi]

Do you really know for sure before you fall down

 

When braking in a straight line, you can safely lock the front momentarily to find the absolute limit, but willingly locking up in a corner takes far more skill than I have.

 

For me, it's about feel, I cannot put it down to science. Just before locking up, the front feels alsmost like it's skating and I "know" I do not have any grip left for steering or turning. Most tyres will also howl a little at this stage, but it depends on the tyre and the road surface.

 

Since I don't race but stick to road riding, I prefer to err on the side of safety. Hence I will try to avoid maximum braking - that's for stopping for a deer etc. - and ease off the brake as I reach more and more lean. Since my built-in tiltometer usually cry uncle before I run out of cornering grip, I can leave a little bit of brake pressure on throughout the corner if I want/need.

 

Again, it's just a feel thing for me and as mentioned, I do not willingly go on search for the limits during cornering. As long as the front end isn't unloaded from running out of cornering clearance, in my experience lesser tyres will tend to gently slip-grip and make me run a little wide if I get close to the traction threshold. It has happened, but I do not like it on the road.

 

Then again, what seems to me as the very limit will probably just mean it's time to shift some body weight etc. to regain traction for an expert because compared to Rossi & Co I do not have a clue about what's going on. Not a clue.

[Jaybird180]

I've only pushed the front once and didn't do it again (backed off the pace a bit). It happened so fast and was over before I knew it. I've yet to overwhelm the rear on the gas.

 

I suppose you can sneak up on the limit

[Fajita Dave]

Low traction and sliding is something I'm very familure with because of my off-road backround. My sportbike does react quite a bit differently to slides but the feel is the same and you need to use the same inputs to correct it.

 

The only way to know you are using all of the availible traction is to get the tires on the very edge of sliding, however, to make that useful is a bit more complicated. In order to use all of the availible grip you need to find the traction limits first. To safely find those traction limits you need to slowly increase your pace and load on the tires until they start to slide. If you don't slowly work you're way up to it you may push straight past that traction limit and you will wreck, like Jaybird said you need to sneak up on the limit. It is CRITICAL to be smooth and consistant. If you suddenly overload a tire you will suddenly lose traction and possibly crash. Riding those traction limits throughout a corner like the pros requires you to feel what the tires are doing and know what inputs to make on the brake, throttle, and lean angle to maintain control of the bike. I'm sure there is something in this paragraph that could be added or adjusted by someone more experience to doing this on-road then I am.

 

Using all of the availible traction still doesn't mean you'll get going fast. To drop lap times having the right braking points, turn in points, on throttle points, pick up points, along with possibly other referance points that as a whole make up your racing lines are way more important that just using all of the availible traction the bike has. Only after having a fast basic racing line will pushing traction limits really lower your lap times.

 

I have never tried these kinds of things on my sportbike because I can't afford to wreck it but I have had a few accidental slides on it. I am always riding on the traction limits of my dirtbike but its much easier to save both the front or rear slides on the dirtbike. My CR250R has also proven to be almost bullet proof as well . I have wrecked on my dirtbike way to many times to keep track of and most of them were because of front end slides. If you suddenly push past your traction limits you will suddenly wreck like I said before and you wont learn a single thing because of it. When you slowly search for that limit you can find it very easily when you try it again and learn how to control the situation.

[stuman]

Hmm, so it is "feel" thing that can't be put into words?

 

You should approach it gradually...

 

 

 

So if the tire slides you have reached the limit of available traction?

 

Is there any warning as you approach your max?

 

We are not just talking about using all your traction on the brakes, using it all on the gas would be more important to me.

 

 

I'm a racer and I'm not advocating searching for the limits of traction on the street. However, I know there are probably a few people on this forum that are interested in going faster around a race track. To do that, at some point, you need to start searching for the limits of traction and attempting to use all your available traction. I have seen a lot of riders with great lines, markers, body position, etc. that weren't going nearly as fast as they could, they weren't willing to use all of what was available to them. The point of performing a lot of the basic techniques is to maximize your available traction.

 

So break it down and be specific if you like. How do you know how much traction is available on the exit of a corner? How about mid corner (front or rear)? Entry?

 

If it is a "feel thing" then what are you feeling?

[Jaybird180]

On exit, you can freely spin the rear. I don't think it's possible to .... nevermind, you can wheelie the front on exit, who cares, right?

 

Midcorner you can slide both F/R

 

Entry you can slide the front, if you have the skill.

[faffi]

Hmm, so it is "feel" thing that can't be put into words?

 

Considering your occupation and who you work for, the answer is with all probability that yes, you can put it into words

 

It still doesn't prevent even the best of the best to get caught out, so obviously the transition from grip to slip can at times be very abrupt and the line too narrow for even riders like Pedrosa or Stoner or Rossi etc. to be able to react at all before they are down.

 

In my opinion, this suggests that you cannot just use logic or break it down to specifics and always make it work. Apparently - and this fit with my own experiences - various tyres have different characteristics. Some may have a very wide window between where they start to slide until they actually let go completely, others will have a razor edge and hence be far more demanding to reach the limit on. Then you have tyres that doesn't act consistently, which must be the worst.

 

Personally, I feel that the tyres feel vague when they start to let go, a sensation as if they are slightly floating over the road surface. It's not a feeling I enjoy much, and the faster I go, the less I like it.

[Fajita Dave]

Keep in mind sliding will slow you down! You need to stay on the edge of sliding to use all of the availible grip. Once the tires are sliding they lose grip.

 

For me when a tire starts sliding while leaned in a corner it just feels like its falling out from under me. I can't really think of any other way to describe it. Off-road the slides are much bigger and depending on the surface grip increases with the slide because the tire digs in more so its very easy to feel. On-road the more you slide the more grip you lose which does vary from tire to tire like Eirik said. Rear tire slides are so much easier to feel and correct then front slides. The rear of the bike really does just feel like it just starts falling out from under you. In that situation just hold the throttle steady or possibly let off the throttle just slightly and pick the bike up so your closer to the center of the tire. That should get the slide under control in a nice controled way. If you chop the throttle with the rear end sliding out of line from the motorcycle it will try to snap back straight which can result in a high-side.

 

Sense my on-road experience is a bit limited I'll leave it at that. Keith wrote an artical that goes into way more detail then I could and its easier to understand :-p. Along with a lot of information that I don't know enough about. Here is the link http://forums.superbikeschool.com/index.php?showtopic=877

[stuman]

It still doesn't prevent even the best of the best to get caught out, so obviously the transition from grip to slip can at times be very abrupt and the line too narrow for even riders like Pedrosa or Stoner or Rossi etc. to be able to react at all before they are down.

 

In my opinion, this suggests that you cannot just use logic or break it down to specifics and always make it work.

 

 

We at the school are kinda all about using logic to break stuff like this down to specifics. That's kinda the point of this thread. Might not always work, but if we can find something that will work a large percentage of the time I think it is a worth while discussion.

[stuman]

So let's here it people, don't be afraid to post up your thoughts. Let's here from some others...

 

 

What do you feel for? How do you know how much traction is available ?

[khp]

Keep in mind sliding will slow you down! You need to stay on the edge of sliding to use all of the availible grip. Once the tires are sliding they lose grip.

Tell that to Gary McCoy - he was sliding everywhere, and its wasn't exactly the slow way around the track when he was riding GP500.

 

So let's here it people, don't be afraid to post up your thoughts. Let's here from some others...

 

What do you feel for? How do you know how much traction is available ?

 

On my small Polini "DreamBike" loosing the front (by putting too much weight on the knee) was quite undramatic - I simply noticed that I was going straight instead of doing a turn, so pressing the front tire into the tarmac would fix that instantly. Mind you, that the Dreambike weighs 20kg and I weight around 90kg including gear.

 

On the big bike, sliding the front has been from vertical to horizontal in less than a blink of an eye (but slow enough to be able to think "oh ######, this will get expensive" before hitting the tarmac).

 

I have slided the rear twice (both not on purpose) - both times it was the feeling of the bike just going sideways underneath me, with no warning. Probably very close to what Fajita Dave calls "falling out under me":

The first time was because a cager in front of me was putting down a nice oil mist on the Nordschliefe. I came up to the next corner (taking it veeeeery easily) and suddenly the rear stepped left, moving my angle of direction maybe 15 degrees or so tighter in the turn.

Second time was on the exit of a fast, heavily banked left-hand turn on Anderstorp Raceway. The bike stepped out, gripped, decided not to highside me, and wobbled a few times (meanwhile my mind went "ok lowsiding ... highsiding? no, lowsiding the other way ... no! it stayed upright (phew - let's go into the pits next time)"). A fellow rider said I had laid down maybe a 10m line of rubber in that turn.

 

To my mind, I have absolutely zip feeling of when I'm close to sliding the rear and how to detect this. This clearly limits my laptime improvements, since I don't ride as hard as I clearly could in the turns (I'm doing 1:12 laps on Ring Knutstorp, where the lap record for bikes is just under 1:00)

[faffi]

It still doesn't prevent even the best of the best to get caught out, so obviously the transition from grip to slip can at times be very abrupt and the line too narrow for even riders like Pedrosa or Stoner or Rossi etc. to be able to react at all before they are down.

 

In my opinion, this suggests that you cannot just use logic or break it down to specifics and always make it work.

 

 

We at the school are kinda all about using logic to break stuff like this down to specifics. That's kinda the point of this thread. Might not always work, but if we can find something that will work a large percentage of the time I think it is a worth while discussion.

 

 

 

Sorry if it sounded like I was implying otherwise - I was more hinting that the theories are flawed in actual life for some reason or the other in that even the best of the best cannot always adhere to them. Probably because we as humans aren't sensitive enough to put them to use under all conditions. A bit like knowing how all robbers look like, but since nobody can cover 360 degrees 24/7, you can still get robbed

[faffi]

Keep in mind sliding will slow you down! You need to stay on the edge of sliding to use all of the availible grip. Once the tires are sliding they lose grip.

 

Keith wrote an artical that goes into way more detail then I could and its easier to understand :-p. Along with a lot of information that I don't know enough about. Here is the link http://forums.superbikeschool.com/index.php?showtopic=877

 

As long as you know what you are doing, sliding the tyres will make you faster. Top rank riders use sliding to quicken the steering and whatever, they gain several seconds per lap from it.

 

Actually, to be absolutely correct, you cannot accelerate or decelerate without slip. And slip is sliding. And steering needs acceleration of some sorts. So what we are talking about here is the transition between controlled slip and a complete lock-up. Also, I suppose a tyre can be locked up in one direction and rolling in another, which would be sideways sliding under speed.

 

BTW, I followed and read the link you pasted, and it - to me - failed to give any new answers to what's been discussed under this topic.

[stuman]

I think something that seems to be coming to light is that often slides happen abruptly and without warning. When this happens is is very hard to react. Sometimes you get lucky and freeze up, which is often the best course of action, do nothing.

 

I think that there are other circumstances when the slide is less abrupt though and in these cases it is possible to react.

 

The description of having the rear wheel "falling out from under you" or ""going sideways" is important. When the rear wheel starts to come out of track with the front it is a pretty clear indication that the rear wheel has lost traction. The further you let that type of slide go the harder it will be to "catch" it and recover.

 

I think the rear wheel tends to slide like this when at greater lean angles. If the bike is really leaned over and the rear wheel starts to slip it tends to "step out" more. If the bike is more upright and your feeding in enough power to get the tire to spin some, it will still stay in line and you don't feel the rear getting out of track.

 

With regards to abrupt front slides. I think the front has a MUCH greater tendency to slide abruptly if you are on the brakes. Which is why trail braking can be such a dangerous proposition. Conversely, if you can carry enough corner speed to push the front a bit, the slide is less abrupt.

 

 

 

Keith conveyed some interesting information to me he got from a tire tech. What I took away is that tires provide their maximum traction with about 10% slippage. So I take that to mean if you are 100% hooked up, you still have a ways to go before you are actually using all of what is available.

 

 

 

 

 

 

 

Let's here from some others that haven't posted in this thread yet. I'm interested in others thoughts on this subject. Post up

[Jaybird180]

Keith conveyed some interesting information to me he got from a tire tech. What I took away is that tires provide their maximum traction with about 10% slippage. So I take that to mean if you are 100% hooked up, you still have a ways to go before you are actually using all of what is available.

 

I thought that 10% slip meant 90% hooked-up. What are you saying now?

[spthomas]

So let's here it people, don't be afraid to post up your thoughts. Let's here from some others...

 

What do you feel for? How do you know how much traction is available ?

My answer is also "I'm not sure". So far I haven't had either end slide out but I'm not the fastest guy on the track either. My last track day was raining in the morning, so I rode around in the wet just to get some experience with it. I wasn't sure but the back end felt a little loose in the turns but then I began to wonder if it was my imagination due to increased expectation of something, or reality. Some guys I talked to afterwards said if you think it's moving, it probably really is.

 

I was thinking about this the other day; the visual I had was walking around the flat roof of a really tall skyscraper, blindfolded. So far I haven't fallen off the edge, but will my feet detect at least a rounded edge to the roof or will I step off into space and fall? I don't know the answer, but this is why I'm looking forward to trying out the slide bike at school someday to find out.

 

So far what I'm hearing and learning is- going into turns, braking hard- the front is at risk- try to feel, and listen. Coming out of turns, getting on the gas hard, the rear is at risk- try to feel.

[Fajita Dave]

As long as you know what you are doing, sliding the tyres will make you faster. Top rank riders use sliding to quicken the steering and whatever, they gain several seconds per lap from it.

 

I guess its just a difference in what you call sliding. Sliding to me is when the tires are past any useful point of slip like Gary Mccoy rides . I still don't understand how he could run fast lap times with the rear tire 2ft out of line through a corner. Tire slip to me would be within that useful 10% stuman mentioned.

[stuman]

I thought that 10% slip meant 90% hooked-up. What are you saying now?

 

 

100% hooked up plus 10% slip.

[faffi]

Wow - is that even mathematically possible

[stuman]

My answer is also "I'm not sure". So far I haven't had either end slide out but I'm not the fastest guy on the track either. My last track day was raining in the morning, so I rode around in the wet just to get some experience with it. I wasn't sure but the back end felt a little loose in the turns but then I began to wonder if it was my imagination due to increased expectation of something, or reality. Some guys I talked to afterwards said if you think it's moving, it probably really is.

 

I was thinking about this the other day; the visual I had was walking around the flat roof of a really tall skyscraper, blindfolded. So far I haven't fallen off the edge, but will my feet detect at least a rounded edge to the roof or will I step off into space and fall? I don't know the answer, but this is why I'm looking forward to trying out the slide bike at school someday to find out.

 

So far what I'm hearing and learning is- going into turns, braking hard- the front is at risk- try to feel, and listen. Coming out of turns, getting on the gas hard, the rear is at risk- try to feel.

 

Thanks for sharing your thoughts Stevo.

 

I think the guys at the track day were probably right, it was moving

 

I think many riders have the same feeling about traction as you in that they want to find that limit but aren't sure what to expect.

 

I'm not so sure about the trying to listen to the front tire thing. I've never used that as a tool and I think using any of your attention trying to listen for some warning might not be all that productive. Your $10 is probably better spent elsewhere.

[stuman]

Ok let's get more specific.

 

 

For those of you that have had a front slide on pavment without falling, what did it feel like?

[Hotfoot]

Ok let's get more specific.

 

 

For those of you that have had a front slide on pavment without falling, what did it feel like?

 

Bike suddenly leaned over farther, feel from the front got really quiet, as if the pavement was glassy smooth, and the front stepped out to the right (wide). Then it hooked up, felt like it stood back up a little, and proceeded on. I never moved, because it happened quick and I had no idea what was going on until I felt the abrupt regain of grip.

 

I've also had a front slide that went all the way to a low-side (at pretty low speed) and it felt similar - I turned the bike and got to my desired lean angle, and then it leaned over more (without me doing anything), and I thought, wow, I'm really leaned over, then my knee touched down and then some part of the bike started scraping loudly and I knew I was going down. In both cases the feedback from the front seemed to get really smooth, which I assume is what people mean when they say "no feedback", the bike leaned over noticeably more, and the front stepped out a little wide, making the bike feel pointed to the outside a little bit.

 

For rear slides, I've just felt the back of the bike come out of line with the front; didn't notice a change in feel or feedback from the rear tire. I've never spun it hard enough to hear the RPMs come up. A rear slide under braking (no rear brake involved) feels very similar to me as a rear slide under acceleration - just the realization that the back is getting a little sideways; I assume I am just noticing that my hips just got pushed a bit to the left or right, relative to my hands on the bars! I'm sitting in a swivel chair here as I type, and if I keep my hands on the keyboard and twist the chair a little one way of the other, that pretty much reproduces the feeling.

[GregGorman]

Ok let's get more specific.

 

For those of you that have had a front slide on pavment without falling, what did it feel like?

 

Great questions, Stu.

 

On my FZ-1 it went like this,

 

I was slightly leaned to the left and the front turned to the left. I wasn't really locked into the bike with my knees and when the bars turned, I almost fell off the bike. I got off the brakes just in time for the bike to stabilize. It was a reactive action as opposed to a thought action.

 

Since then I've locked up/slide the front a few more times, mostly at Daytona - must be the hard tires. Sliding when braking, it's really hard braking and I'm feeling everything then the it just gets vague and I'm decelerating a bit less - the weight on the front lightens up just a bit.

 

In turns, the front slides before I get on the gas. The front turns sharply into the turn and the bike just falls away. Allowing the front to turn like that and getting on the gas saves it. Sometimes I feel the slides before they happen, most times I don't. It's just traction, traction, traction, WHOA! what was that? I think being loose enough on the bars and allowing the front to turn in is the only thing giving me enough time to get on the gas.

 

It's happening enough, especially when I push on older tires, that I'm starting to get a feel of the braking forces and lean angles. Ah, feel is the wrong word. I have an idea of what lean angles and speed will cause the slide and can predict it.

[harnois]

I have seen a lot of riders with great lines, markers, body position, etc. that weren't going nearly as fast as they could, they weren't willing to use all of what was available to them. The point of performing a lot of the basic techniques is to maximize your available traction.

 

My evaluation of my own riding is that it fits that description. But from my perspective the issue is all about quick turning. A lot of turns only last 2 to 4 seconds. So if you don't get it leaned 100% instantly, there's just no time to find the edge. And so when riding around VIR North course, which has a lot of esses, I rarely even feel limited by traction. I feel limited because I know if I go faster I won't be able to turn the thing fast enough to keep it on the line, especially in high-speed esses.

 

And that's not to say that my quick turning ability is not good, but no matter how good your technique or your bike setup, there's always a limit to how fast a given rider can flick his bike. And it's not just a matter of quickness but accuracy, because if we get too carried away we can flick it too far. During no brakes drills I work on quick turning and it helps a lot. As with any sport, to execute the moves with top level accuracy and quickness takes a huge amount of practice.

 

And you've got to be able to accurately judge turn entry speeds. To run through the turn at the right speed to be on that edge, you've got to dedicate yourself to that speed from the beginning of the turn, and that also takes time to work up to without sending yourself into panic mode. And the harder you charge into the turn, the more pressure you are under to get that turn-in done quickly and accurately. It's not like you can just ease into the turn and then grab a bunch of throttle mid-turn to get up to the speed that would put you on the edge. It's not just a matter of having the guts to lean it lower - it doesn't do any good unless you've got the speed to go with it. It takes time to gradually increase ones turn entry speeds.

 

Then consider that available traction is constantly changing due to dips and rises and bumpiness, and so imagine how much judgment it really takes to be able to ride that edge in all scenarios. That's what sets the pros apart in my opinion, they are able to run that edge at every moment around the track.

 

As you get closer and closer to that edge, you've got to everything more smoothly, more quickly, and more accurately. It takes some serious practice time.

 

Boneheads think they aught to be able to run on the ragged edge despite their lack of practice time and fundamental technique.

 

... how much traction is available ...? ... If it is a "feel thing" then what are you feeling?

 

The "falling out from under you" feeling that other posters are discussing here, to me is a sensation that only occurs when you suddenly jump passed the limit, like when you hit a patch of gravel. In the few moments I've had on the track where I felt I was really riding the edge but not going over it was a subtle drifting or shimmying feeling that did not really change the lean angle in a scary way. But I've only really felt this occasionally when cresting a rise or riding on a cooked rear tire, so its not like I have a lot of experience with it. But even a intentional power slide on a dirt bike doesn't feel to me like anything is falling out from under me.

 

Although I don't think you will be able to put into words exactly how much traction is available or how you feel for it, I do think the fundamental techniques taught at the school help the rider approach that edge with more confidence and feel. For example, quick turning gets you to maximum lean quick, allowing more time to feel out the edge. Staying loose on the bars means that when the rear slides a bit you'll feel the bar naturally turn relative to the rest of the bike giving you more sense of what is happening. And better body position and being locked onto the bike facilitates that loose grip and the quick turning. And accelerating mildly throughout the turn balances the front to rear traction and increases stability which makes slides a lot less scary when they happen.

[Bullet]

Ok let's get more specific.

 

 

For those of you that have had a front slide on pavment without falling, what did it feel like?

 

Bike suddenly leaned over farther, feel from the front got really quiet, as if the pavement was glassy smooth, and the front stepped out to the right (wide).

 

That's a great description of how it feels hotfoot!

 

Bullet